Spark-indicator and plug-tester



J. S."S'TEVENSON. SPARK INDICATOB AND PLUG TESTER.

APPLICATION FILED APIMZQ. I918.

' iPatented Aug. 3, 1.920.

2' SHEETS-SHEET 1. I

Ufa/"mega E W E, Grammy v J. S STEVENSON. SPARK INDICATORANDPLUGl-TESTER.

APPLICATIONYFILED APR. 29. 1918,

1 348,456. Patented Aug. 3, 1920..

2 SHEETS-SHEET 2.

STAE

FICE.

SPARK-INDICATOR AND PLUG-TESTER.

' Application filed April 29, 1918. Serial No. 231,506.

To all whom it may concern Be it known that I, JoI-IN S. STEVENSON, acitizen of the United States, residing at Baltimore and State ofMaryland, have invented certain new and useful Improvements inSpark-Indicators and Plug-Testers, of which the following is aspecification.

This invention relates to an improved spark indicator and spark plugtester for internal combustion engines and has as its primary object toprovide a device of this character including auxiliary spark gapsadapted to be respectively included in circuit with the spark plugs andwherein the said auxiliary spark gaps will be easily visible so that theoccurrence of a spark at any one of the said gaps may be readilyobserved and the proper flow of current to the plugs thus alwaysdetermined.

The invention has as a further object to provide a construction whereincorresponding terminals of the auxiliary spark gaps will be readilyadjustable with respect to the coacting terminals of the said gaps foreither closing the circuits at the gaps or varying the length of thesaid gaps to accordingly test the efiieciency of the respective sparkplugs.

A further object of the invention is to provide a construction whereinthe terminals which are mounted for service adjustment will be normallyhoused within the casing of the device but wherein the said casing willbe provided with a door which may be opened to permit ready access tothe said terminals.

And the invention has as a still further object to provide a devicewherein the imposition of auxiliary spark gaps in the circuits of thespark plugs will prevent leakage of the current through the plugs suchas might be caused by defective insulation and will consequently alsoguard against possible resultant injury to the coils of the ignitionsystem.

Other and incidental objects will appear as the description proceeds. Inthe drawings wherein I have illustrated the preferred on the line 2-2 ofFig. 1, and particularly showing the manner in which tie device ismounted 1n posltlon, j

v Specification of Letters Patent.

Patented Aug. 3, 1920.

Fig. 3 is a vertical sectional view taken on the line 3-3 of Fig. 1, andparticularly showing the mounting of the terminals or electrodes of theauxiliary spark gaps of the device,

Fig. dis a horizontal sectional view taken on the line 4-4, of Fig. 3,

Fig. 5 is a similar view takenon the line 5-5 of Fig. 3,

'Fig. 6 is a rear perspective view showing the upper section of thecasing of the device detached,

Fig. 7 is a view similar to Fig. 6 and illustrating the bottom sectionof the casing of the device detached, and I Fig. 8 is a fragmentarysectional view showing a slightly modified structure.

In carrying out the invention I employ an oblong casing including a bodysection 10, a bottom section 11, and a top section 12. The body sectionis formed of suitable insulating material while the top and bottomsections may be constructed of wood. As

particularly shown in Fig. 7 of the drawings, the bottom section is-madeup of complemental mating members 13, secured together by a plurality oftransversely extending screws or other suitable fastening devices 14:and connected at its ends with the body section by vertically disposedscrews or other approved fastening devices 15 fitted loosely through thebottom section and threaded into the body section. Formed through thebottom section, at suitable longitudinally spaced points thereon, is aplurality of open- I ings 16. The top section 12 is also, asparticularly shown in.Fig. 6 of the drawings, made up of complementalmating members 17 and 18 respectively. The member 17 is connected at itsends with the body section 10 by screws or other suitable fasteningdeyices l9 fitted through the said member and threaded into the bodysection while the member 18 is connected with the member 17 by suitablehinges 20 and forms a door adapted to open upwardly and outwardly withrespect to the body section. Connected with this door is a catch 21 ofapproved character for normally holding the door closed. Formed throughthe member 18 of the top section at its lower rear edge and through theadjacent upper edge of the body section 10 is a plurality of openings 22spaced longitudinally of these sections to conform to the spacing of theopenings 16 in the bottom section. Connected with the body section 10adjacent the extremities are vertically disposed. alitachina;- brackets23 screwed or oiherwise secured no lihc said section and provided. atEheir e);- treniities with lalterally direcied attaching; lugs 2iadapted to bolls or other liars telling means lor conncciiing thecasing: to the ins'lriunent board of a nioi'ior vehicle as conventionallv indicated at llowever, while l have indicated lhal; i'he device maythus be connected with the vehic e instruiueul board. ii: will. olcourse, be understood that the said device may be mounted upon any orher(auivenient partof the vehicle or. when used in counecbion wihh anengine other than a motor vehicle engine may be mounted in any suitableplace desired convenient lo l'he engine, it being understood lhat thepresent invention. is adapted nol; only lor use in connection with theor 'nes of motor vehicles but also in connection iriih iulernalcombustion ei'iggincs employed for other purposes. Nevertheless, foreonyeir icnee l shall in describing the invention, refer to its use inconnection with a motor vehicle engine.

Formed in the body section ll) of the casing plurality of cylindricalsparking chambers :26 which open through the from; laceof the said.section in provide window openings and are diametrically enlarged ail--jacent their outer extremities. Sealed against the shoulders thus formedin the chambers are transparent closures or windows 27. These closuresmay be formed of mica or other approved material and are rcniovably heldin place by spring retaining rings 28. As particularly brou z hl out inFigs. 1, and 5 of the drawings, the

i are each provided wiih a thereof closures 2i darkened annular marginfor excluding the greater portion of the light t in she parlc ingchambers while the ccnaers of the said closures are iuidarhened so lliaia spark occurring wilhin any one oi" the said chambers may be readilyobserved through its window. Threaded through the body section ll) fromthe bottom face lhereoi? to project at their inner ends into thesparking chainbers 26, is a plurality of terminals or electrodes Theseterminals are received through suitable recesses 30 formed in the bottomface of the said section to register with the openings 16 of the bottomsection ll and at their outer ends are provided with squared heads 3].normally projecting within rhe said openings and adapted to receive aWrench for adjustably rotating: the terminals. [is will be seen, thisresult may be readily accomplished by simply removing the said bottomsection. However, while the terminals are thus adjustable, it is Jintended that such adjustment shall be prao 'ticahy permanent so thatthese terminals may thus be considered as relatively fixed terminalsThreaded into the outer ends of reasons the terminals axially thereofare clamping screws 32 by means of which circuit wires 3-3 may, asparticularly shown i. Fig. 3 of the drawings, be connected with the saidterminals. These circuit wires are, at the adjacent ends thereof,wrapper with suitable tape or otherwise formed to wedge within the outerportions of die openings l6 so as to preserve neat joints between thesaid wires and the casing and are respec tively connected al; theirGpPOSitG cngh .0 the several spark plugs of the vehicle engine.

Formed in the top face of the body section flu oppositelthe recases 230lthereii'i, a illlll'l'llllly recerses lid-into which the openings 29enter and threaded through the body section axially of these recesses isa plurality oil sleeves 35. Loosely litied over the said. sleeves wilhinthe E l-l: are suitable washer 3b ehrizraded upon the ano sleeves toconfront these washers are nuts 37 adjusiable to clamp lrhe inher endsof circuit wires 38 between the nuts and the said washers. These circuitwires enler through the openings and at their inner ends arz' tightlyclamped therein to preserve neat joints between the wires and the casingwhile the opposite ends of the said wires are r ':l.ivi.y connected withl-he several coils in log a part, of the ignition system oi. the vehicleengine. it is now to be observed that the complemental mating membersoi? the top seclion 12 of the casing are out away upon their confrontingsides to pro vide a. plurality of recesses l-O overlying: the recesses34 in the top face of the body section and receiving the upperextremities of the sleeves 35. The sleeves are internally threadedadjacent their inner em s and adustable 'hrougrh the said sleeves arescrew terminals or electrodes -21 projecting at their inner extremitiesinto the sparking chamliers $26 of the body section in alinement withthe relatively fixed terminals 229. 'Ali their upper extremities theterminals ll are received within the recesses section and are equippedwith annular heads 42 of suiiuable insulating" material. Bearing betweenthese heads and the nuts 37 are tensioning springs -13 yieldably holdingthe said i erz'oinals and nuts at adjustment.

As will now be clear, the pairs of coacting terminals 2.) and oil willform auxiliary spark naps within the sparking chambers .26 and theseauxiliary spark gaps will be interposed in the circuits of the enginespark plugs. Consequently, each time a circuit is closed through theseveral wires 88, a

Bill

4.0 of the top jump spark will occur within one of the sparking chambersand since the wires are prel erabl v connected with the spark plugs ofthe engine in the order of firing of the cylinders thereof, it may thusbe readily dchmnined, by observing; the jump sparks in the sparlrinchambers through the winleakage of current through the plugs, such asmight be caused bydefective insulation,

will be overcome, since current can flow,to

the plugs only when the voltage of the current has raised suflicientlyto jump the auxiliary spark gaps. v

As particularly brought out in Fig. 3 of the drawings, the terminals 41will be inclosedand housed by the upper section 12 of the casing whenthe door of this section in closed. However, by opening this door accessmay be readily had to the said terminals. Consequently, by grasping theheads 32 of the terminals, these terminals may be easily adjusted withvrespect to the terminals 29 for varying the length of the auxiliaryspark gaps and, since the heads of the termina-ls are formed ofinsulating material, this operation may be performed while the engine isrunning. The terminals 41 may thus be regulated for varying the lengthof the auxiliary spark gaps under working conditions of the engine toaccordingly obtain the most effective operation of the ignition sys-.tem'thereof while, in a similar manner, the

said terminals may also be adjusted to engage the terminals 29 to thusclose the circuits therethrough for testing the spark plugs in a'mahnerwhich will be well understood. Upon the setting of the terminals, thesprings 43 will prevent their accidental displacement from adjustedposition.

It will, therefore, 'be seen that I provide a particularly eflicientconstruction forthe purpose set forth and while in the present instanceI have shown and described the embodiment of my invention as applying toa four-cylinder engine still, it will, of course, be understood that thedevice may be readily modified for use in connection with engines havingeither a greater or less number of cylinders.

In Fig. 8 of the drawings I have shown a slight modification of theinvention which relates more particularly to the-provision of centrallyapertured light screens in connec tion with the closures for thesparking chambers. In this figure, one of the sparking chambers isindicated at 43. The window ofthis chamber is closed by a transparentclosure 44. Seating against the outer face of this closure is.a lightscreen 45 which may be constructed of a darkened piece of mica or otherapproved material for shading the outer margin of the closure to excludethe passage of light therethrough. The screen 45 is held in position bya spring retaining ring 46 similar to the rings 28 of the preferredconstruction. In some instances it may be found preferable to enigaicythis light screen of the modified structure in iieu of the colored ordarkened closure proper as illustrated in connection with the preferredforin of the invention. v

Having thus described the invention, What is claimed as new-is:

1. A device of the character described ineluding a casing provided witha sparking chamber, a sleeve opening into the chamber,

coacting terminals projecting into the chamber and forming a spark'gaptherein,vone

of said terminals being fitted through the sleeve and rotatablyadjustable thereon with respect to the other of the terminals, meansadjustable upon the sleeve for clamping a circuit wire in engagementtherewith, and yieldable means bearing between said first mentionedmeans and the adjustable terminal for holding such terminal atadjustment and also holding said first mentioned means at adjustment.

2. A device of the character described comprising a body section and topand bottom sections mating with the body'section, fastening meansconnecting said sections, the body section being formed with a sparkingchamber and the bottom section with an opening, a terminal fittedthrough the body section into. the chamber and accessible through saidopening, and a terminal normally housed within the top section ,andprojecting through the body section into said chamber to coact with saidfirst mentioned terminal.

3. A device 'of the character described including a casing comprising abody section, and a top section includingia fixed member connected tothe body section, and

a movable member hingedly connected to Y the fixed member and providinga door for the said top section, the body section being provided with asparking chamber, a .rela-' tively fixed terminal carried by the bodysection to project into the said chamber, and

a terminal adjustable upon the body section and projecting into the saidsparking chamber to coact with the said first mentioned terminal, thesaid adjustable'terminal up-v section, one of said terminalsprojectingwithin the top section and being accessible upon the openingof said door.

Tn testimony whereof I affix m signature.

JOHN S. STEVENSO [n s.] Witness:

W. H. PAIRO.

